Modeling ion effects for the Argonne Advanced Photon Source upgrade

Journal Article · 15 November 2019 · Physical Review Accelerators and Beams

DOI: https://doi.org/10.1103/physrevaccelbeams.22.114403 · OSTI ID:1607560

Calvey, J. ^[1]; Borland, M. ^[1]

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1. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)

Ions are produced in an accelerator when the beam ionizes residual gas inside the vacuum chamber. If the beam is negatively charged, ions can become trapped in the beams potential, and their density will increase over time. Trapped ions can cause a variety of undesirable effects, including instability and emittance growth. This paper will discuss the possibility of ion trapping and instability in the APS-Upgrade storage ring. The question of where ions will be trapped is addressed using simple analytical calculations, while the instability is modeled with computer simulations. A scheme is proposed for mitigating the ion instability, by using train gaps with a high charge bunch before and after the gap to minimize rf transients. The reduction in ion density due to nonevaporable getter coating is also discussed.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC); USDOE
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1607560
• Alternate ID(s): OSTI ID: 1798841
• Journal Information: Physical Review Accelerators and Beams, Vol. 22, Issue 11; ISSN 2469-9888
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English